Spark plug



April 29 1924. 1,492,515

H. JOHNS SPARK PLUG `Filed Nov. 2, 1920 eat-maa apr. ae, tesa HUGH JOHNS, 0F WELLINGTON, OHIO.

SPARK PLUG.

Application led November 2, 1920. Serial Nfo. 421,244.

To all whom t may concern.' Y

Be it known that I, HUGH JOHNS, a citizen of the United States, residing( at Wellington, in the county of Lorain and State of Ohio, have invented certain new and useful Improvements in Spark Plugs, of which the following is a specification.

My invention relates to improvements in spark plugs.

An important object of the invention is to provide a spark plug having electrodes so constructed or shaped, that the oil will not remain near the firing point, but draw back or drip away from the same, so that carbon will not be deposited at the tiring point, causing the usual short circuit, such electrodes providing a firing surface of sufficient area, to prevent the electrodes being burned at the ring point, whereby the spark gap would be widened.

A further object of the invention is to provide a device of the above mentioned character, which is formed of few and simple parts, and which may be manufactured cheaply.

A further object of the invention is to provide a spark plug with electrodes having a knife edge, allowing the electrodes to reach a sufficiently high degree of heat, to burn the carbon deposits therefrom.

Other objects and advantages of the invention will be apparent during the course of the following description.

In the accompanying drawings forming a part of this specification, and in which like numerals are employed to designate like parts throughout the same,

Figure 1 is a side elevation of a spark plug embodying my invention,

Figure 2 is a side elevation of the electrodes included in the same.

Figure 3 is a horizontal section taken on line 3--3 of Figure 1.

Figure 4 is a side elevation of a spark plug embodying a slightly different form of my invention, and,

Figure 5 is a side elevation of an electrode included inthe second form of spark lu p I the drawings, wherein for the purpose of illustration are shown preferred embodiments of my invention, the numeral 10 designates the metallic body portion or casing l of a spark plug, Figures 1 and 4, having a reduced tubular screw-threaded portion 11, to engage within the usual screw-threaded opening in the engine cylinder. The casing -10 receives the usual insulator 12, held therein byv a` gland or ring. nut 13. i

The numeral 14 designates an inner electrode, preferably circular throughoutits upper portion, and held within the insulator 12. kThe upper end yof the electrode 14 may be screw-threaded,'at 15, to receive the usual binding nut 16. At its lower end, the electrode 14 has its opposite sides flattened, providing an arrow-head 17, having faces 18, which converge outwardly forming knife edges 19, as shown. The edges 19 converge upwardly above the points 20, and converge downwardly below these points, as shown. This construction is common to Figures 1 and 4. The arrow-head 17 also has its lower tapered portion 21 converging upon the faces 18, whereby the knife edge continues about the lower end of the arrow-head.

In Figures 1 and 2 the numeral 22 designates a coacting electrode, secured to the metallic tubular extension 11, and hence insulated from the electrode 14. The electrode 22 carries a head 23, having opposite faces 24, converging toward their edges, to form knife edges 25, extending about the point of the head 23.' The head 23 is longitudinally curved and its upper portion diverges upwardly from the arrow-head 17 and its lower portion diverges downwardly from the lower portion of the arrow-head. There is an intermediate portion 26, forming with the adjacent portion of the arrow-head, a sparking surface of substantial area, for instance substantially one-eighth of an inch, suoli area being indicated by the transverse dotted lines 27.

In Figures 4 and 5 an electrode 28 is provided, extending straight in a downward direction, and having an angular upwardly extending head 29, which is flattened and provided with knife edges 30. The lower portion of the head 29 converges downward ly from the lower portion of the arrowhead 17.

In use, bv virtue of the shape of the arrow-head 17, and the angular arrangement of the coacting electrode, any oil tending to accumulate at the sparking point or gap, will drain away from the same, which action is aided by the knife edges. These knife edges also heat to a sufficiently high temperature, whereby any carbon accumulating at or near the sparking point will be burned off. vThe electrodes provide a sparking point or space of suiieient area to prevent the electrodes being burned, with the result that the spark gap is widened.

It is to 'be understood that the forms of my invention herewith shown and described are to be taken as preferred examples of the same, and that various changes in the shape, size, and arrangement of parts may be resorted to without departing from. the spirit of my invention, or the scope of the subjoined Claim.

Having thus described my invention, I claimzf A spark plug of the character described, comprising a metallic body portion, an insulator carried thereby, an electrode carried by the insulator and having an arrow-head,

HUGH JOHNS. 

